!!!!!Valve Clearances!!!!!

hi there I'm going though the pratice of checking / setting the valves. I'm having a bad run. I've tryed 6 different brands shapes and sizes of feeler blades and not yet found a set to clear cylinder head casting or cam retainers .......I've over come the problem by removing the cams and checking clearance with PLASTI-GAUGE much more accurate way of checking in my eyes

Keep shopping. The angled feeler gauges seem to work best. All of the gauges I have tried are a tight fit width wise. I wish I could find narrow angled ones.

You shouldn't have to check clearances more than once every few months, unless your mileage is very high.

Scott F

cheers for the help guy's I have tryed the snap on feeler blade theye were the best fiting of the lot but still couldn't get a good movement in the tappet....( not accurate enough for my liking.

Many thanks


Having just checked the valve clearances on my mates '99 Wr400 , we were horrified to find that the clearances were less than half of what they should be ( those that we could get at anyway !! )

We are pretty sure they have not been looked at since new , so it is unlikely they have been adjusted wrongly - but why would they wear TIGHT ?

Also , why would they need checking every 500km ? you dont check them at such regularity on Superbikes - and most cars dont need checking until 60,00 km or more !

Are we all paranoid over valve clearances , or are WR cams made from ice cream ?

They "wear tighter" because the valve head and valve seat have been rubbing against each other and wearing a bit which allows the valve to 'sink' into the head a little bit...therefore 'tightening up' the clearance on the stem end... I think you will find that after the initial adjustment there is not much wear and you will only have to adjust them once a year, but maybe check them twice a year.

My experience was I had to adjust two of the intake valves at about 800 miles and no other adjustments since (approx 3500miles on bike now). I check the valves every three months and have found very little change since the initial adjustment.


snap-on do a narrow angled feeler guage set.

The best feeler gauge to use is the Yamaha recommended gauge from Kent-Moore tool company. The blades are 5 mm wide and 100 mm in length and fit nicely. The part number is YM-34483. You will have to order it from a Yamaha dealer though as Kent-Moore only sells this tool to dealers.

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